A dual-beam laser processing system that uses polarized beams derived from a single laser to produce two target specimen processing beams can undergo coherent crosstalk stemming from a significant portion of one beam leaking into the propagation path of the other beam. Coherent crosstalk arises when the two beams derived from the single laser are purposefully combined in a common beam path through a portion of the optical train and are subsequently reseparated. Because of the coherent nature of the two beams, any leakage of one beam into the propagation path of the other beam at the reseparation stage leads to coherent crosstalk, which is substantially more severe than that which would be present if the beams were mutually incoherent. Coherent crosstalk causes degraded pulse energy and power stability control of one or both of the laser beams at the working surface of the target specimen.